Physical Processes and Models of Interplanetary Responses: Suggested Theoretical Studies

Abstract

Three ways to improve the theory and therefore the understanding of the physical processes in the interplanetary medium (during both quiet and disturbed periods of solar activity) are suggested. They are: (1) the development and consequently the use of higher order moments (fluid) equations as well as of more realistic closure conditions and transport coefficients for the macroscopic description of the solar wind; (2) the undertaking of computer simulation experiments on the nonlinear collective relaxation process through particle-wave-particle interaction due to the plasma electromagnetic instabilities which may develop under conditions prevailing in the solar wind; and (3) the consideration of collective interactions in the evaluation of the transport coefficients, as deduced from the quasi-linear theory and computer simulation experiments, and their incorporation into the higher order moment equations.